Research On Torque Characteristics Of Pre-opening Guide Vane In A Pump Turbine

The reversible water pump-turbine play an important role in distributed energy storage and regulation in the Energy Internet,and are the core energy conversion equipment in pumped storage units.Pumped storage,as th e world’s most mature energy storage technology,is also an important means of optimizing China’s energy structure,while also facing some challenges.In recent years,some accidents caused by abnormal operation of the guide vane caused by the unusual oper ation of the guide vane often occur during the operation of the unit,which affects t he stable operation of the unit,this paper begins to study the hydraulic torque characteristics of the guide vanes of pump-turbine.Many existing research results show that the installation of misaligned guide vanes can modify or even eliminate the "S" characteristic of the pump turbine.Therefore,this treatise focuses on the influence of the pre-opened guide vane opening and layout schemes on the hydraulic torque of the guide vanes.A turbine storage power station was taken as the research object,using a turbine test rig of an engineering center of a domestic research institute to calculate unsteady constant values for the model machine based on the test results.This article mainly focuses on the influence of the pre-opened guide vane opening and arrangement on the hydraulic torque of the guide vane,and explores the inflow characteristics and pressure pulsation in the vaneless zone under different opening degrees and different arrangements of the pre-opened guide vane.The main research contents are as follows:1.Conducted a model test study of the guide vane hydraulic torque of the pump and turbine operating conditions,introduced the basic conditions and param eters of the test rig,and the experimental scheme.Through experimental measurements of the guide vane hydraulic torque,it was obtained that there is no pre-discharge under the turbine operating conditions.The distribution of the hydraulic torque of the guide vane and the guide vane with the pre-opened guide vane,the synchronous guide vane hydraulic torque shows a linear decrease trend with the increase of the active guide vane opening degree,and the change law is the same;when the pre-opened guide vane participates,explore The use of pre-opened guide vanes has an effect on the hydraulic torque experienced by adjacent synchronous guide vanes.When the pre-opening guide vane is involved,the opening of the synchronous guide vane exceeds 25 mm,and when the difference between the openings of the two is about 8mm,installing the pre-opening guide vane within this range will improve the force situation;2.The influence of the pre-opening guide vane opening degree on the hydraulic torque characteristics of the guide vane was studied.The combination of experiments and numerical simulations is used to conduct experimental and simulation research on model machines with different openings of misaligned guide vanes.The internal flow regime and pressure conditions in the wheel region were quantitatively analyzed for the influence of the pre-opening guide vane opening degree on the hydraulic torque characteristics of the guide vane and the pressure pulsation in the vaneless region.The results show that the pre-opened guide vanes lead to the disorder of the flow state.The larger the opening degree,the stronger the disorder,which has a certain negative effect on the guide vane hydraulic torque,but effectively improves the movable guide vanes and the surrounding force situation.Comprehensive consideration,when the four pre-opened guide vanes are arranged at an equal distance,the pre-opened guide vane opening degree is most suitable;3.After determining the suitable opening degree of the misaligned guide vanes,explore the effect of the different arrangement and number of pre-opening guide vanes on the force of the movable guide vanes.The three-dimensional unsteady numerical calculation of the full-flow channel of the model water pump turbine was carried out,and the effects of different arrangement and number of pre-opened guide vanes on the hydraulic torque of the guide vanes and pressure pulsation characteristics in the vaneless zone were compared and analyzed.It is concluded that when the number of pre-guided vanes is constant,compared with the centralized arrangement,the hydraulic torque value of the misaligned guided vanes in a symmetrical arrangement is smaller and the periodicity is better.With the same opening degree of the misaligned guided vanes,the number of misaligned guided vanes was increased from 2 to 4,the torque value was significantly reduced and the change was gentle,and the amplitude was also reduced.The flow in the runner is axisymmetric.